Karzahni is an ancient being -- one of the first in existence in the Bionicle universe -- who rules a place named after himself. According to Matoran legend, in the time before the Great Spirit, Matoran labored in darkness. Those who worked well were sent to Artakha and were allowed to work in the light, while those who worked poorly were sent to Karzahni. However, it has been since revealed that "poor working" Matoran who came to him were really just injured or broken and in need of repair.

Karzahni has headed to Mahri Nui with an army of Manas, in effort to expand his territory, where he had become mutated.

Although the set is titled Karzahni -- this set comes with two other beings as well: the Ta-Matoran Sarda and the Ga-Matoran Idris.